Power transmission chains have been constructed of sets or ranks of interleaved links, the adjacent sets or ranks of which have been connected by pivot means of various cross-sections. Some of the pivot means are multiple members while others are a simple pin. The links of such chain are all generally the same, i.e., links having a pair of toes separated by a crotch, the toes being defined by outside flanks and inside flanks, the latter joining to define the crotch. Such chains have been designed to drivingly engage sprocket teeth with the inside flanks or with the outside flanks. Historically the outside flank engagement has been used with industrial power transmission type chains while the inside flank engagement has been used with automotive timing or motion transferring type chains.
One of the factors to be considered in modern automotive use is the noise generated by the impact at engagement of the chain with a sprocket. Too high a noise level is objectionable. Attempts to reduce the noise levels have been made by modifying the sprockets, either by varying the number of full size teeth on the sprockets, relieving the roots of the sprocket teeth or relieving the flanks of the sprocket teeth. Examples of such attempts are taught by U.S. Pat. Nos. 3,377,875, granted Apr. 16, 1968, 3,495,468, granted Feb. 17, 1970 and 4,168,634, granted Sept. 25, 1979, all assigned to General Motors Corporation.